Figure 1

Regional tectonic setting and location of the study area. Solid lines indicate plate boundaries. The rectangle is the region shown in Figure 2. Red dots indicate the epicenters of low-frequency earthquakes along the Nankai Trough from January 2006 to December 2010. Stars indicate the epicenters of the 1944 Tonankai and the 1946 Nankai earthquakes. Labels A to D show locations of long-term slow slip events (SSEs) along the Nankai Trough observed by GPS. A: Tokai (Suito and Ozawa 2009). B: western Shikoku (Kobayashi 2010). C: Bungo Channel (Hirose et al. 2010). D: Hyuga-nada (Yarai and Ozawa 2013).